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VENTILATION, WEATHER AND 

THE COMMON COLD 

A Study of the Prevalence of Respiratory 

Affections Among School Children and 

Their Association with School Ventilation 

and the Seasonal Changes in Weather 



BY 

GEORGE T. PALMER, M.S., Epidemiologist, 

Detroit Department of Health 



Reprint from 

THE JOURNAL OF LABORATORY 
AND CLINICAL MEDICINE 

St. Louis 



Vol. VI, Nos. 11 and 12, Vol. VII, No. 1, August, 
September, and October, 1921 



V /> 



VENTILATION, WEATHER, AND THE COMMON COLD 



Study of the Prevalence op Respiratory Affections Among School 
Children and Their Association with School Ventilation 
AND THE Seasonal Changes in Weather 



By George T. Palmer, M.S., Epidemiologist 
Detroit Department of Health 



introductory 



DURING the last twenty years there has been a great amount of experimental 
work on ventilation and its effect on the body. Workers in Europe and 
the United States are in substantial agreement that it is the thermal factors — 
temperature, air motion and humidity — which exercise the greatest influence 
on human comfort, health and efficiency. The chemical composition of the 
air we ordinarily breathe — leaving out of consideration for the moment those 
special industrial problems involving gases, fumes and dusts — is of relatively 
little moment in its effect on human conduct. School children are far better 
off in a cool, airy room, regardless of the carbon dioxide content of the air, 
than they are in air virgin pure chemically which is overheated. 

It is most important that the facts as we have stated them should be 
clearly understood, for otherwise, there is bound to arise, as there has in 
the past, a misunderstanding as to the suitability of different methods of 
ventilating school buildings. 

if variable, as opposed to uniform, temperature, air motion and humidity 
are desirable factors, then very satisfactory conditions can be maintained in 
school rooms by ventilating with the windoAvs, protected by deflectors, and 
an exhaust duct on the opposite side of the room, heating being by direct 
radiation beneath the windows. This method of ventilating will not always 
give good aeration. At times the room will be amply flushed with outside 
air. At other times, due to shifting winds, the circulation will be lessened, 
the room will not be thoroughly flushed, and the carbon dioxide content 
Avill rise, indicating an accumulation of the products of exhalation and body 
vaporization. Even though the aeration of the room fluctuates, it is possible 
to have coolness at all times and variability, and if the room is cool and 



*This is an abridged form of a dissertation presented in partial fulfillment of the requirements for 
the degree of Doctor of Public Health at the University of Michigan, 1920. 

This study was conducted jointly by the Bureau of Child Hygiene of the New York City Depart- 
ment of Health, represented by Dr. S. Josephine Baker, Chief of the Bureau, and the New York State 
Commission on Ventilation, represented by the author, who then held the position of chief of the in- 
vestigating staff. The collection of sickness records and the taking of temperature and other observations 
on air conditions was done by nurses and physicians of the Health Department under the supervision of 
Drs. Li. Marcus and R. H. Willis. The routine clerical work of tabulation was likewise conducted by the 
Health Department under the immediate direction of Dr. Franklin Van Wart. The planning of the 
investigation, selection of schools, initial instruction of the field staff and the final analysis and interpreta- 
tion of results is largely the work of the author. 



variable within certain limits it makes little practical dii¥erence as to the 
humidity. 

On the other hand, if the experimental data of the last two decades are 
wrong in minimizing the relative value of chemical purity of the atmosphere, 
then windoAv ventilation as we have described it is inadequate, and it will be 
necessary to insure at all times voluminous and continuous flushing of the 
room with outside air. This can be done only by mechanical means, that is 
by plenum fans or blowers. 

There has existed for some time a controversy as to the relative merits of 
natural and mechanical ventilation. An inheritance from the days of Pet- 
tenkofer, when chemical purity was regarded as vital, has kept alive the 
carbon dioxide content as the standard of ventilation goodness. This 
standard persists to this day. Measured in these terms the window venti- 
lated room falls into disrepute. A carbon dioxide standard of 6 to 10 parts 
per 10,000 automatically throws any form of window ventilation into the dis- 
card. It is only by mechanical means that this degree of chemical purity 
can be at all times assured. 

"With the development of mechanical ventilation there has grown up an 
impression that uniformity in temperature, in air motion and in humidity is 
ideal, and again the mechanically forced ventilation far excells the gravity 
method in this respect. Furthermore the dust in outside air can be removed 
readily under the mechanical system by the introduction of air washers. This 
is not possible with window ventilation. 

There is much then that can be accomplished with the plenum system that 
is not possible under the window method. The question arises as to whether 
the superiority of the mechanical system is superficial, a matter of a relatively 
unimportant refinement so far as the school classroom is concerned. The 
drawbacks to the mechanically ventilated classroom are its tendency to over- 
heating, its unstimulating uniformity and its greater expense. 

There is much to be said on both sides. The advocates of window ventila- 
tion are impressed by its success with tuberculously inclined and undernour- 
ished children. It has a wide application in our public schools at the present 
time. If good for sick children, why not for well children? Is window ven- 
tilation in the schoolroom to be ruled out of consideration merely because it 
fails to live up to the carbon dioxide standard? It was for the purpose of 
testing out these principles on a practical scale that the present experiment 
was undertaken. After all, the proof of the pudding is in the eating. If 
the health of school children, as measured by the amount of respiratory illness, 
such as colds, tonsillitis, etc., is better under the more elaborate systems 
of mechanical ventilation, then let us proceed to equip our buildings in this 
manner. If, on the other hand, the mechanical ventilating equipment does not 
supply substantial benefits to the health, comfort or efficiency of our school 
child population, or is actually inferior in the things that count for health, let 
us face the matter squarely. 

There are innumerable demands for public funds. If we are paying out 
vast sums of money for benefits Avhich are not real but imaginary, recognition 



of this fact cannot come too soon. If window ventilation provides the im- 
portant essentials of a healthy atmosphere in a way that cannot be attained 
or improved upon by mechanical systems of indirect ventilation, then our 
school buildings should be built accordingly, and we should not hesitate because 
a worn out standard of ventilation dictates otherwise. 

During the latter part of 1916, from February 14th to April 6th (8 weeks), 
and the winter of 1916-17, from October 30 to January 26 (12 weeks), observa- 
tions were made on the health of 5500 New York City school children who 
were exposed to various types of ventilation in 12 different school buildings. 
In general these ventilation" systems may be classified under three main 
headings, as follows: 

A — Cold, open window rooms, gravity exhaust. 

B — Cool, window ventilated rooms, gravity exhaust. 

C — Plenum, fan ventilated rooms with gravity exhaust and -with windows 
closed. 

As an index of health, the sickness records of the pupils were used. The 
condition of the air was determined by readings of temperature and humidity 
and by the personal sensations of the observers as to temperature, moisture, air 
motion and odor. It would have been desirable to determine also the carbon 
dioxide content of the air, but this involved analytical work which the staff 
was unable to do. The absence of these latter data was not serious, however, 
for the Ventilation Commission had available a mass of data on this subject 
collected over two years' time, and it was well established that the carbon 
dioxide content of fan ventilated rooms averages several parts lower than in 
window ventilated rooms. 

For the convenience of the reader we shall reserve the description of work- 
ing methods and ventilation types in individual schools for the later pages 
and shall proceed with an account of the findings of this study. 

RESULTS OF SICKNESS SURVEY IN DIFFERENT TYPES OF VENTILATED SCHOOL ROOMS 

The first half of the study in the spring of 1916 covered 2500 pupils in 
58 classrooms distributed among 8 schools. The second half in the winter of 
1916-17 was represented by 3000 pupils in 76 classrooms in 12 schools. 

In both studies the absences due to respiratory illness and the respiratory 
illness among pupils present in school was greatest in the fan ventilated rooms, 
Type C. This is the result after combining all records and disregarding in 
this instance the balancing of the type of pupil, location of school, etc., which 
will be treated more at length later on. 

The excess of respiratory illness in the Type C rooms holds good both 
for absentees and those in school. The total illness is least in the second 
group, or cool, window ventilated rooms. The difference, however, between 
the first and second types of window ventilation is less than between either the 
first or second and the third. In other words, assuming for the moment that 
these differences are due to atmospheric influences, the air conditions in the 
first two types do not produce greatly divergent effects, but the influences at 
work in the third type are distinctly less favorable. 



The significance of these two sets of results maj' be expressed in this man- 
ner; for every 100 cases of respiratory illness in the cool window ventilated 
rooms, there are 152 in cold, window ventilated rooms, and 231 in fan venti- 
lated rooms. 

Table I 
Respiratory Illness per 1000 Registration 
(Pupil-Session) Units* 



Ventilation 
Type 



FIRST STUDY 
Among Among 

Absentees Pupils 
in School 



second STUDY 

Total Among Among 

Absentees Pupils 
in School 



Total 



A-Cold, Window Rooms 10.6 37.2 47.8 9.2 75.3 84.5 

B-Cool, Window Rooms 10.2 22.1 32.3 10.7 44.1 54.8 

C-Fan Ventilated 1A2 76^0 90^2 13^0 98.4 111.4 

Table II 
Basic Figures from which Rates in Table I Are Computed 



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FIRST STUDY 








second 


STUDY 






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61,658 
71,231 
65,088 



655 

728 
925 



2,298 
1,578 
4,950 



89,067 
113,959 
115,215 



822 
1,218 
1,497 



6,705 

4,661 

11,329 



The actual temperature conditions found in the three types of rooms are 
disclosed in the two tables following, in one of which results are expressed as 
averages, and in the other by temperature groups. 



Table III 
Average of Room Temperatures 



Ventilation 
Type 



First Study 



Second Study 



Mean 



A 
B 

C 



58.8 
66.9 
68.8 



59.1 
65.9 
67.9 



59.0 
66.4 
68.4 



*The unit of illness was one pupil per half-day school session. Illness is reported in pupil session 
units. One pupil ill ten sessions counted the same as ten pupils ill one session. A piipi! was continued 
on the register regardless of the length of absence from school unless it was found that the family had 
moved away from the school district, or that the pupil had left school permanently. 

Separate tabulations have been made of illness resulting in absence from school and illness among 
pupils who continued to attend school. The absences are classified as (1) absence from respiratory illness, 
including coryza, bronchitis, pharyngiti.s, laryngitis, tonsillitis, pneumonia, tuberculosis and a miscellaneous 
group variously termed gripjie, colds, sore throat, etc.; (2) absence from illness other than respiratory, 
namely: stomachache, backache, broken leg, etc. In this group were also the acute infectious diseases 
such as diphtheria, measles, scarlet fever, whooping cough, chickenpox, mumps, etc. This was done be- 
cause it was felt that the spread of these infections was largely determined by specific susceptibility 
rather than by atmospheric influences; (3) absence due to causes other than illness, such as staying 
at home to mind the baby, going on a visit, shopping with parents, truancy, etc. 



The fan ventilated or Type C rooms averaged but two degrees higher 
than those of Type B and nearly ten degrees warmer than Type A. Type 
A was extremely cold for a school room. Type B was cooler than is cus- 
tomarily found. The average temperature of Type C, though higher than B, 
was not exceptionally high. 

There was a wide range in the daily temperatures, which are lost sight of in 
the averages. 

Table IV 

Frequency Distribution of Temperatures 

Per Cent op Sessions 



Types 












Ventilation 


59° 


and beloTv 




60-69° 


70° and over 








1st Study 






A 




56 




41 


3 


B 




5 




61 


34 


C 




4 


2nd Stiidy 


57 


39 


A 




46 




48 


6 


B 




8 




88 


4 


C 




0.2 




99 


0.8 



The A rooms rarely reached 70°. Fully half of the sessions were below 
59°. The B and C rooms rarely fell below 60°. The temperatures in the 
second study were much more uniform, particularly as regards Type C and to 
a lesser extent Type B. More than one-third of the sessions in B and C in the 
first study were above 70°. Much of this represented an overheated condition. 
However, the first study was made in the late winter, when greater outdoor 
variation is experienced than from November to January. Although the pro- 
portion of sessions between 60 and 70° does not appear to differ much in the 
B and C rooms, yet there was an appreciable difference within this range. 
Thus, in the first study 24 per cent of sessions in B were from 60° to 64°, 
whereas but 6 per cent of the sessions in C were within this range. Thirty- 
seven per cent of B sessions were from 65 to 69 as against 51 per cent of the 
C sessions. The C rooms were warmer, as the averages have already indicated. 

The interesting point to be noted is that whereas there was but two de- 
grees difference in temperature between the B and C rooms, there was a wide 
difference in the sickness rates. Between 7 and 8 degrees separated Types A 
and B, and yet in spite of this the sickness rates were quite similar. Evi- 
dently some factor other than temperature operated differently on these three 
classes of rooms or else a rise of two degrees above 66° is far more conducive to 
colds than a drop of as much as 7 degrees. 

HUMIDITY 

The relative humidity ranged from 38 to 46% and did not differ greatly in 
the three classes. 

As would be expected, the relative humidity was higher in the colder 
rooms. "With the same amount of moisture present as in Type A, the relative 
humidity in the first study at the temperature in Type B would be 33.4, 



Table V 
Relative Humidity 



Ventilation First Study Second Study 
Type 

A 43.7 46.3 

B 37.8 43.0 

C 37^8 4L2 

and in Type C 31.4. The corresponding figures in the second study would 
be 29.9 for B and 28.7 for C. It would appear, therefore, that there was an 
accumulation of moisture in the Type B rooms, and this could only come 
from reduced aeration. In Type C the same explanation would hold. The 
rooms at P. S. 59 were humidified, as were also the rooms at P. S. 51 and 97, 
but this would hardly affect the average of all rooms in the group to this 
extent. It is also possible that the taking of the humidity reading was not 
as accurately done in the dry rooms, the wet bulb being read before the mer- 
cury column had completed its fall. These readings are higher than Ave should 
expect at this season of the year, judging from records taken by the Com- 
mission in similar rooms in other schools. 

Other indices of air conditions were the opinions of the nurses who visited 
the rooms at least twice daily. 

FRESHiSTESS AND ODOR 

The results of the nurses' votes on the freshness or lack of freshness and 
presence of odor in the rooms are given in Table VI. 

Table VI 

PERCENTAGE OF SESSIONS JUDGED 

Ventilation Exceptionally Odor Absent but Odorous 

Type Fresh not Exceptionally 

fresh 

A 62 24 14 

B 25 57 18 

C 21 64 15 





First Study 




62 




24 


25 




57 


21 


Second Study 


64 


69 




28 


18 




62 


22 




67 



A 69 28 3.2 

B 18 62 20 
C 22 67 11 

The results are very interesting from several points of view. The Type 
B rooms are most odorous in both studies. The excess over the others was 
slight in the first study, 18, as compared to 15 for Type C and 14 for A. It 
was more marked in the second study, 20, as against 11 for C and only 3.2 
for A. 

The freshest rooms are the coldest rooms. Sixty-two per cent of the 
sessions in Type A in the first study were judged exceptionally fresh, and 
in the second study the figure was 69 per cent. The figures for Type B were 
25 per cent in the first and 18 in the second. Type C had 21 per cent in the first 
and 22 per cent in the second. 

8 



What seems clear from these figures is that to be exceptionally fresh the 
greater part of the time, rooms must be well below 65 degrees in temperature. 
Warmer rooms may be free from odor and yet exceptionally fresh not much 
over one-fifth of the time. 

In rooms that did not differ greatly in temperature, as B and C, the 
greater aeration produced by fan ventilation reduced odor to a slight degree 
in the first study, and to a marked degree in the second. It failed to make 
the rooms any fresher in the first study, but did help out in the second study. 

Although we do not possess complete records of the carbon dioxide con- 
tent, there is little doubt but that the smallest amount would be found in the 
fan ventilated rooms, Type C, as we have already pointed out. Eepeated 
records collected in three schools show this tendency (Table VII). 

Table VII 
Carbon Dioxide in Parts per 10,000 

SCHOOL ventilation TYPE 

B C 

33 O 5^5 ' 

115 7.6 6.5 

97 8.6 5.7 



The markedly greater freshness of the Type A rooms is due, without ques- 
tion, to their low temperature, and not because of the greater chemical purity 
of the air. Freshness is not a question of odor, for the Type B rooms were 
fresher than C and yet more odorous. 



SENSATION OF TEMPERATURE 



The recorded votes of the nurses as to whether the temperature of the 
rooms felt "too cool," "satisfactory" or "too warm" are given in Table VIII. 



Table VIII 



PER CENT OF SESSIONS JUDGED 
VENTILATION TOO COOL SATISFACTORY TOO WARM 



TYPE 



A 7.9 77 16 

B 6.2 78 16 

C 10 76 14 





First Study 




7.9 




77 


6.2 




78 


10 


Second Study 


76 


26 




70 


8.6 




80 


3.6 




85 



3.9 
11 
12 



In the first study the per cent of satisfactory sessions was about the same 
in all three types, being in the neighborhood of 77 per cent. There were more 
sessions judged "too warm" in Types A and B than in C, although the average 
temperature was lower than C. The "too cool" sessions were most numerous in 
Type C, the rooms of highest temperature. In other words, the coldest rooms 
felt warmer than the warm rooms. In view of the actual temperature found, it 
would appear that the nurses were influenced in their judgment of what the 



temperature should have been rather than by actual sensation. In no other 
way can we account for the votes in rooms whose temperature differed by at least 
ten degrees, as was the case in Types A and C. 

The votes in the second study more nearly reveal the actual temperature 
condition as indicated by the thermometer. In A 26 per cent of the sessions 
were judged "too cool." In fact, 4 per cent were voted "too cold" — an ex- 
treme condition. In Type B, 8.6 per cent were "too cool" and in C 3.6 
per cent. 

Type C had the greatest number of sessions judged satisfactory as to tem- 
perature ; namely, 85 per cent. The corresponding figure for Type B was 80 
and for A, 70. 

Too great warmth was experienced 12 per cent of the time in C, 11 per cent 
in B and but 3.9 per cent in A. 

The sensation of temperature reflects the actual thermometer reading — to 
some extent at least. There was much lesss overheating in the second study, 
and this agrees Avith the lesser number of "too warm" votes. 

SENSATION OF MOISTURE 

As will be seen from the figures given below, over 80 per cent of sessions 
in all three types of the first study were judged satisfactory as to moisture. 
Both moisture and dryness were most pronounced in Type C. 

Table IX 

PER CENT OF SESSIONS JUDGED 
VENTILATION MOIST SATISFACTORY DRY 

TYPE 

A 5.9 88 6. 

B 1.7 89 9.0 

C 7.3 83 9.7 





First Study 




5.9 




88 


1.7 




89 


7.3 


Second Study 


83 


33 




66 


20 




74 


8.5 




84 



A 33 66 0.6 
B 20 74 6.4 
C 8^5 84 7.9 

The second study reveals a greater divergence between the rooms. Type 
C had the highest percentage of satisfactory sessions, 84. Type B had but 74 
per cent and Type A, only 66. The cooler sessions are associated with moisture, 
the warmer sessions with dryness. One-third of all sessions in A were 
moist and less than 1 per cent dry. Twenty per cent of sessions in B were 
moist and 6.4 per cent dry. Eight and five-tenths per cent of C were moist 
and 7.9 per cent dry. 

There was less overheating in the second study and the sensation of 
dryness is less. Type C is similar in both studies. The other two types are 
different in that the second study shows many more moist sessions. 

AIR MOTION 

The greatest proportion of satisfactory votes as to air motion was found in 
A. Moving air was noticed most frequently in A and least in B. The results 

10 



of both studies are similar, although it is surprising to find the sessions in 
Type C judged "dead" to be more numerous in the second study where the 
air flow through the rooms was greater and the temperature was lower. 



Table X 
Per Cent of Sessions Judged 



VENTILATION DEAD SATISFACTORY 

TYPE 

A 4.7 81 14 

B 15 78 7.1 

C • 9.3 73 18 





First Study 




4.7 




81 


15 




78 


9.3 


Second Study 


73 


9.2 




74 


18 




75 


23 




68 



A 9.2 74 17 

B 18 75 7.0 

C 23 68 9.8 



ANALYSIS OF SICKNESS RATES IN INDIVIDUAL ROOMS AND SCHOOLS 

AS we have pointed out in the introductory remarks, great care must be 
taken in drawing conclusions as to the correlation of different facts from 
the average results of a group. In the study before us it will be necessary to 
inquire into the records of each school and of the individual rooms to see 
whether they agree uniformly with the characteristics of the group. 

In Tables XI and XII are assembled records for each room covering the 
nature of air conditions and the amount of respiratory sickness. 

It is noticeable that there is a wide variation in respiratory illness. Koom 
415 (Type B) at P. S. 22 in the second study had no absences whatever from 
respiratory illness. Room 311 (Type C), P. S. 115, in the second study, has a 
rate of 50.4. These represent the minimum and maximum limits. The range 
of respiratory sickness-in-attendance rates is even greater — from zero to 316. 

Eoom 311, P. S. 59 (Type A) is the most congested in the first study, 
there being but 6.5 square feet of floor space per pupil. In spite of this 
crowded condition, the absence rate from respiratory disease is only 0.6 — one 
of the lowest. On the other hand. Room 202, P. S. 165, being the least con- 
gested, with 19.6 square feet per pupil, has a respiratory absence rate of 37.0, 
a very high figure. Overcrowding does not inevitably lead to respiratory 
illness. 

The average temperature of Type A rooms was about 59 degrees in both 
studies. This is much colder than the ordinary school room. In fact, it 
seems from our general experience entirely too cold for public school children, 
and yet, on looking over the absence rates, there is no indication that these 
children had more colds as a result. In fact, the average absence rate for the 
entire group is lower than the other two ventilation types, as has already 
been pointed out. In the first study there are only two rooms in Type A with 
rates over 20. There are three each in Types B and C. Respiratory sickness 
among those present in school is greater in Type A than in B, but less in A 
than in C, 

In spite of the well intentioned efforts to balance the three types of rooms 
in the rriatter of schools and type of pupil, this coul4 not be carried out to 

II 



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r-I 03 05 1^' 10 



<t^ pq <i pq pq pq 
-th 00 in m TjH "^ 



rH -^ CO o o o 

10 ^ lO 



iH "* O CO W 



C<J O C» Cl ffi_ rJH O N CO O IC >A -^ tH lO CO «0 CO O 

cdodcocdco od-^io'-^'-^ coThioinod looicdeq 



<i1 <j^ <ii pq pq <|<ii<ipqpq pq pq <i pq <^ <J pq <1 pq 

co-rtHin-*"* -rtHioio-^io kOinco-^io Tf<coTt<io 



00000 OOrHb-Ol TfHlO<CiO 
00000 OOTj<v5t<CO co-*co 



o 00 in «o CO iH 



CO O -* 1-i 



CO CO t^ O CO l>- 
•^ Ti< T^ CO CO <M 



O in rfH 05 CO 
CO (M (M -^ ^ 



CO 00 t^ 01 o 
TtH tji tJ< T}( m 



O O 00 CO CO 

in m CO CO CO 



k 



C<l CO 00 t^ CO 



CO -* o in iH 



OJ CO CO 

o o o -*' 

CO ai r-I 



00 00 ^ Tj< t^ 00 s 



in CD cq TiH ^ in in C5 00 00 co o -tH o in cq 03 00 w 
C5 00 ai 00' t^ go' 00 00 t-' t>^ 00' 06 co' 00 t^ o' CQ o o 

COCOCOCOCO COCOCOCDCO COCDCOCOCO t^l>-t~t~ 



coT}Hcoi>-cqoj ^cqinwiHin cooioiooTH cooitMOi— 1 cooocmco 

•*' i-i tJH r-I CO Co' "B b-^ Co' O l-i cd Tj? ■^' CO CD CO* -*" OS ■^' -rtH iH l>^ Qc' iH m" 

^t^cocoi-Hcq coocomt^ ooint^co coi-noi-^ 

<o (MrHiHiHrHrH rHi-| 



iH CO CO Ttl t^ 



w 

H 


■^ iH 05 in 


(?q 05 ^_ ^ b-. TtJ 


Iz; 


>H 1-! in r-i 


CO 0' 0' in co' 


H 


C4 r-I rH 


iH I-i i-i cq 



uO CO 00 iH CO 
O O r-t 1-H tH 
CO t}< CO Tt< ^ 



r-jcqojcooiin wt^ccirHOTfi cocoooinincoooo^o 

r-! rH co" r-i l>^ b-^ ■» rji <m' b-' rji Cq in 00 Gi O CO CO* b-' in (M* i-I CO* iH* CO CO 

(MccicoTiH Siicoco-^ T-i (M00T)HTfico oiOi-^t^cci coQoinco 

>3 iH T-H iH iH iH 



ooocooin oiOiOiooTtH oco^jHinco oocqo 

CO * CO b-^ o' od CO t-^ CO* O 00 oci 00* rH OS •^' b-^ in CM 
r-i rH r-< rHrHt-HrH rH COCOCOi-H 



b-t~OCqCO TfHTflrH in rH COinOrtlln rHOdOOO 
OOrHOO OOOOO OOrHOO OOCqO 

(Mcoco-*"* Tt(co-rt<Ttiin mmtMcoco (Mcqoqco 



in CD 00 cq CO G3 

O O O O O O 

CO -^ Th CO CO CO 



13 



Table XII 
Records of Individual Booms in Second Study 







RESPIR.A.TORY SICKNESS RATES 






PER CENT 




w 

o 

CO 


1 


m 

w 

is 

< < 


AMONG 
THOSE IN 
ATTENDANCE 


O 


> 

< 




w 

m 

w 


05 

O 
« 

o 

a 
o 


o 
< 

o 








lype A— 


-Cold Open 


Window Booms 








12 


303 


3.9 


46.6 


50.7 


59.9 


58.0 


28 





2 A 




409 


8.1 


13.7 


21.8 


61.3 


54.4 


18 





4 B 




410 


11.1 


14.2 


25.3 


60.3 


56.0 


33 





4 B 


39 


202 


6.9 


65.0 


71.9 


58.7 


41.3 


65 


4 


3 A 




203 


13 


40.0 


53.0 


56.2 


43.4 


72 


2 


4 A 




204 


21.6 


45.9 


67.5 


56.6 


43.1 


72 


1 


3 B 




205 


6.7 


30.3 


37.0 


58.7 


42.2 


46 


7 


3 B 




206 


9.3 


24.9 


34.2 


58.3 


40.3 


55 





3 A 




207 


11.7 


18.4 


30.1 


57.6 


41.4 


60 


2 


4 B 


59 


308 


4.0 


165 


169 


60.0 


48.0 


100 





3 B 




311 


8.5 


144. 


152.5 


58.5 


48.9 


100 





3 A 




313 


26.8 


213 


2.39.8 


59.0 


44.7 


85 


11 


2 A 




412 


4.3 


150 


154.3 


58.1 


45.1 


100 





4 A 




413 


9.2 


147 


156.2 


60.0 


48.0 


98 


2 


4 B 




414 


3.0 


124 


127 


57.8 


48.4 


100 





4 A 




416 


8.0 


91.3 


99.3 


57.6 


46.5 


100 





4 B 


73 


301 


5.1 


44.1 


49.2 


60.2 


44.8 


71 


2 


5 B 




309 


11.6 


34.8 


46.4 


58.9 


45.9 


67 


2 


4 A 




402 


6.1 


18.4 


24.5 


60.5 


44.7 


72 


5 


6 A 




403 


6.2 


39.4 


45.6 


63.5 


45.3 


50 


29 


5 B 






Type B- 


-Moderate 


Temperature, Open 


Window 


Booms 






2 Bx. 


301 


■ 10.7 


9.7 


20.4 


68.6 


38.5 





13 


2 B 




302 


7.7 


5.8 


13.5 


69.0 


38.5 





23 


2 B 




316 


11.6 


12.2 


23.8 


65.4 


40.0 





24 


5 A 


12 


405 


9.5 


33.2 


42.7 


62.2 


57.8 


6 


1 


4 A 




408 


15.9 


3i;4 


47.3 


63.5 


59.0 


1 


2 


3 B 


12 


411 


9.9 


5.8 


15.7 


63.8 


60.6 


3 


10 


4 A 


22 


415 











67.6 


57.7 


17 


82 


5 B 




416 


5.5 


2.7 


8.2 


68.2 


56.0 


23 


72 


6 A 




418 


.9 


24.6 


25.5 


67.3 


56.7 


29 


65 


5 B 


33 Bx. 


13 


21.4 


55.7 


77.1 


69.3 


31.3 





9 


8 B 




23 


27.5 


47.5 


75.0 


69.4 


37.2 


1 


21 


7 A 


39 


302 


10.9 


33.6 


44.5 


63.0 


40.3 


19 





4 A 




308 


8.6 


42.8 


51.4 


65.0 


37.7 


23 


3 


5 A 




408 


2.9 


58.0 


60.9 


65.2 


39.0 


9 


31 


5 A 


59 


318 


3.7 


187 


190.7 


64.9 


48.5 


4 


61 


3 A 




415 


16.2 


158 


174.2 


58.8 


48.2 


100 





4 B 


73 


305 


9.7 


23 


32.7 


61.6 


46.5 


45 


10 


4 B 




406 


2.7 


41 


43.7 


67.1 


43.3 


17 


35 


3 A 




408 


16 


51 


67 


61.1 


43.6 


74 


4 


3 B 


97 


302 


6.4 


37 


43 


67.0 


38.2 


17 


62 


5 B 




313 


7.1 


50 


57 


67.3 


41.8 


71 


17 


4 A 




501 


3.0 


55 


58 


65.9 


44.8 


59 


18 


6 B 


115 


312 


23.3 


— 


— 


67.8 


28.8 


3 


3 


4 B 




502 


40.2 


— 


— 


67.9 


26.2 


2 


3 


5 B 



M 



Table XII (Continued) 





respiratory sickness rates 




PER 


CENT 


SESSIONS 




. o 
o 
W 
o 

72 


o 
o 


m 


AMONG 
THOSE IN 
ATTENDANCE 


o 

El 


i 


ii 


w 

w 

to 


m 

|3 

o 

OS 

o 
o 


GRADE 




503 


29.8 


— 





67.0 


29.5 





3 


5 B 


165 


302 


1.3 


99 


100.3 


67.2 


35.9 








5 B 




306 


10.4 


56 


66.4 


66.8 


35.7 








4 B 




309 


8.1 


33 


41.1 


68.9 


36.1 








4 B 




Type 


C — Moderate Temp 


., Fan Ventilated, 


Closed Window Booms 




2 Bx. 


207 


22.4 


25.5 


47.9 


66.1 


39.6 





13 


2 A 




307 


13.2 


17.0 


30.2 


65.8 


41.2 





35 


3 B. 




310 


1.3 


3.8 


5.1 


66.5 


41.5 





20 


4 B 


22 


402 


4.8 


5.6 


10.4 


66.5 


57.0 


75 


16 


6 A 




403 


3.5 


1.3 


4.8 


65.8 


56.2 


77 


23 


4 B 


22 


404 


14.4 


18 


32.4 


66.5 


54.9 


66 


17 


4 B 


33 Bx. 


14 


29.3 


23 


52.3 


71.0 


28.6 


1 


2 


6 B 




24 


45.4 


125 


170.4 


70.2 


32.0 


3 


3 


5 A 


51 Bx. 


203 (Hum, 


.) 4.0 


148 


152 


67.6 


43.6 





39 - 


6 A 




205 


14.7 


50 


64.7 


67.4 


29.0 





2 


6 A 


59 


203 


16.8 


182 


198.8 


69.2 


47 


10 


12 


6 B 




205 


13.9 


275 


288.9 


69.2 


45.5 


17 


5 


6 B 




206 


9.9 


316 


325.9 


69.6 


46 


16 


1 


6 A 




501 


12.4 


256 


268.4 


68.9 


49 


7 


6 


5 B- 




503 


9.1 


197 


206.1 


69.2 


47.9 


25 


1 


5 B 




505 


8.3 


112 


120.3 


68.7 


49.3 


2 


13 


6 A 


97 


303 


2.3 


34.1 


36.4 


68.0 


43.1 


84 


2 


4 B 




308 


2.7 


34.7 


37.4 


68.3 


40.2 


79 


4 


5 A 




502 


6.8 


43.3 


50.1 


66.3 


44.8 


91 


3 


6 B 


115 


308 


44 


24.8 


68.8 


67 


27.2 


2 


5 


4 A 




311 


50.4 


51.6 


102 


68.2 


25.2 





6 


4 B 


147 


210 


16.6 


11.9 


28.5 


68.1 


42.4 


30 


13 


3 A 




304 


3.6 


6.8 


10.4 


67.7 


40.4 


22 


36 


4 B 




305 


4.2 


12.4 


16.6 


67.1 


42 


49 


9 


5 A 


165 


201 


11.9 


196 


207.9 


68.4 


33.3 








4 A 




202 


5.3 


151 


156.3 


68.0 


34.5 








3 B 




220 


10 


181 


191 


69.2 


35 








4 A 




308 


1.8 


154 


155.8 


68.7 


35 








5 B 



the degree desired. If the pupils in one district are by reason of hereditary 
and environmental influences more susceptible to colds, then this school will 
unduly raise the sickness rate in the ventilation type within which the major- 
ity of its records fall. 

Of the 12 schools used in the two studies, only one possessed all three 
examples of ventilation. In one other instance the three types were repre- 
sented by two schools a block or so apart, one school having Type C and the 
other, Types A and B. In all other instances there were not more than two 
types represented within a school building, some buildings having A and B and 
others, B and C. The division of rooms is revealed in the table below. 

One can readily appreciate by looking at the table how the results would be 
affected if, say. School 39 were given to very little sickness and School 147 to 

IS 



Table Xlll 
Distribution of Test Rooms among the Tavelve Schools by Ventilation Type 









FIRST STUDY 






SECONb STUDY 








SCHOOL 


A 


B 


C 


A 


B 


C 






12 


3 


p, 





3 


3 









147 








3 








3 






22 





3 


3 





3 


3 






59 


5 


3 


6 


7 


2 


6 






73 


4 


3 





4 


3 









165 





3 


4 





3 


4 






39 


6 


3 





6 


3 









2 Bx. 





3 


3 





3 


3 






33 Bx. 











2 


2 






51 Bx. 














2 






97 











3 


3 






115 











3 


2 






Total 


18 


21 


19 


20 


28 


28 





a great deal. In the summary of all rooms Type A, having 6 rooms in School 
39 Avould have a low sickness rate, not because of ventilation, but because of 
its personnel, and Type C M^ould be inclined to have a high rate, not because 
of ventilation but because of the numbers of children from School 147. Theo- 
retically this influence should have been eliminated at the beginning, but 
actually this was found impossible. 

The total respiratory illness rate including both absentees and those 
present in each school is shown in Table XIV. 

Table XIV 
Total Respiratory Illness Rates by Schools 



SCHOOL 


FIRST study 


second study 


97 


— 


46.7 


22 


100.3 


13.6 


12 & 147 


31.1 


27.9 


73 


■ 37.4 


44.2 


51 Bx. 


— 


106.4 


59 


103.1 


193.3 


39 


12.6 


51.6 


2 Bx. 


55.9 


24.2 


165 


77.9 


123.3 


33 Bx. 


— 


92.6 



A considerable variation is seen in the illness rates. Schools 59 and 165 
are relatively high in both studies. Schools 12, 147 and 73 are low in both. 
School 22 is high in the first study and extremely low in the second. 

We may examine the effect of ventilation apart from these extraneous in- 
fluences mentioned first by inspecting the records of each school by itself 
and secondly by balancing the influence which each school exerts on the total. 

In an effort to illustrate the comparison of illness rates within each school 
we have prepared Charts I and II, the former showing Types A and B and 
the latter, B and C. Both measures of illness among the absent and among 
those present are included. The frequency with which one ventilation type 
exceeds the other in amount of illness conveys an impression that is not bro.ught 
out in the averages for each ventilation type. 

i6 



In the comparison of the window ventilated rooms from the chart, Type 
B exceeds Type A in respiratory illness in nine instances. In the remaining 
seven instances Type A exceeds Type B. There is then no prevailing superior- 
ity of one type over another. It will be noted in the summary at the bottom 
of the chart, where the rates have been averaged, that Type B shows less re- 



COMPARISON OF RESPIRATORY ILLNESS RATES 

IN VENTILATION TYPES A (Cold Open window Room^ 

AND B (Moderate Temperature, Open Window Rooms) 



45. 



I»» Study 



TyfX Rate Ratii 



Ab3e nt 



In 



Afier 



U\ Atfei 



In 



66 
100 
dcnce 



psent 
9.0 
taz 



bsent 



11.6 
75 

Att^ 

39 



45. 



vi6.ee> 



2 nd Study 



dance 



/Ak|ise|nt 
72 79 : 
91 1001 
/\|tte|ncl< ince 



School 



12 



59 



39 



73 



Sumrnary 



Absent 


A 9.7 

B ao 


lOS 


1 




100 


^^^^" 


InAttendonce 


/\ 4Q^\09 


— 1 


B 44JS 


100 





Chart 1. 



spiratory illness than A. This is due to the influence of several high rates in 
Type A. Incidentally this illustrates how an erroneous impression may be 
gained from averages alone. 

In the comparison between Types B and C, the latter exceeds the former 
in respiratory illness in eighteen instances; whereas B exceeds C m only seven 



17 



instances. This result is much more significant than in the previous comparison. 
The averages of the rates are consistent with the tendency of the individual 
instances. With the new schools used in the second study included, the 
average for Type C exceeds B in both measures of respiratory illness. The 
same is true with the new schools omitted. 



COMPARISON OF RESPIRATORY ILLNESS RATES 

IN VENTILATION TYPES B (Moderate Temperature 
Open Window Rooms ) AND C (Moderate Temperature 
Fair Ventilated Rooms) 



mmmv/mmm 



Ist study 



Typ« Rbfe Rat. 



'm/mmm/ m/jm//;m 



70 
iOO 



100 
52 

100 




'>mmm;m//wm//////mm)/»mm 



?ov/m/mm!fmmM/)m»/m/)i)iimimn 



SUMMARY 

Ne w Schools of grid study Included 



A tie 

B 
C 



Af e. 



se 



8z 



nt 



2nd Study 




Tmmsmmmm 



100 

d 
100 



21 



3^7 

n|da 

100 



*K 




'immmmmmmm/mi/m/mmmm ^ 




mmi//imm;////mmmm 



School 



147 



59 



2flK 



165 



Char: II. 

This analysis confirms what has been brought out previously — that the 
difference between Types A and B is insignificant; whereas, between B and 
C there is a distinct excess of illness in the fan ventilated rooms. 

In School 59 all three types of ventilation are represented. "We have in 
this instance a good measure of ventilation influences on pupils of the same 



i8 



general characteristics. The fan ventilated rooms have the greatest respira- 
tory illness in both studies. The relative positions of A and B are not the same 
in the two studies, the cold rooms having more illness in the first study and less 
in the second. 

Table XV 
Respiratory Illness Rates in Three Ventilation Types at School 59 



VENTILATION 




FIRST STUDY 




SECOND STUDY 




TYPE 


SICKNESS 

CAUSING 

ABSENCE 


SICKNESS 

IN 
SCHOOL 


SUM 


SICKNESS 
CAUSING 
ABSENCE 


SICKNESS 
IN 
SCHOOL 


SUM 


A 
B 
C 


4.6 

9.1 

13.7 


90 
53 

L39 


94.6 

62.1 

1.52.7 


9.0 

10.2 
11.7 


148 

172 
223 


157 
182 
235 



The room temperature for each type averaged as follows: 



58.8 
65.4 
68.2 



58.7 
61.9 
69.1 



The fan ventilated rooms were the warmest, exceeding the Type B 
rooms by 2.8 degrees in the first study and by 7.2 degrees in the second. 
These results are consistent in showing less illness in the window ventilated 
rooms. 

In one other instance the three ventilation -types are to be found divided 
between two schools within a block of each other and for all practical pur- 
poses the characteristics of the pupils are the same. The sickness rates for 
Schools 12 and 147 are shoAvn in Table XVI. 

Table XVI 
Respiratory Illness Rates in Three Ventilation Types at Schools 12 and 147 



VENTILATION 




FIRST STUDY 




SECOND STUDY 




TYPE 


SICICNESS 

CAUSING 

ABSENCE 


SICKNESS 

IN 
SCHOOL 


SUM 


SICKNESS 
CAUSING 
ABSENCE 


SICKNESS 
IN 
SCHOOL 


SUM 


A 
B 
C 


9.3 
7.0 
6.5 


8.6 
15 

47 


17.9 
22.0 
53.5 


7.7 
11.7 

8.2 


22 
24 
10 


29.7 
35.7 
18 



(Temperature— 1st Study A 60.5, B 66.6, C 67.3; 2nd Study, A 60.5, B 63.2, C 67.6.) 

The fan ventilated rooms appear to better advantage in this instance, 
for illness is lowest in Type C in the second study. In the first study the total 
illness is greatest in the fan ventilated rooms, although the illness causing 
absence is the lowest of the three types. 

The Type C rooms at School 59 were unusually well equipped with 
mechanical ventilation facilities. The air is humidified before entering the 
room, and the blowers are capably managed. The fan equipment at School 
147 is older and the rooms were not thoroughly aerated at all times, and 
windows were frequently found open. 

In view of the oft repeated assertion that humidification and air washing 
in coml^inatipn with the plenum fan is from many standpoints a superior 



tg 



form of ventilation, the figures of this study are of special interest. A 
modern form of mechanical ventilation with warm temperature is associated 
with more respiratory sickness than naturally ventilated rooms with gravity 
exhaust. On the other hand, fan ventilation, lacking many modern features, 
as in P. S. 147, is associated with less respiratory illness than naturally ven- 
tilated rooms. At P. S. 147 the temperature of the fan rooms was lower than 
at P. S. 59. Eaising the temperature over 68 degrees would seem to be more 
disturbing to health than reducing the volume of air passing through the 
rooms. 

The temperature of the A rooms in all instances was lower than those se- 
lected as B rooms. In general the C rooms were warmer than B, although 
there were some exceptions to this. 

Table XA^II 

Average Temperature and Total Eespiratory Illness Rates by 

Ventilation Types in Each School 







FIRST 


STUDY 


SECOND 


STUDY 


SCHOOL 


VENTILATION 
TYPE 


TEMP. 


RATE 


TEMP. 


RATE 


12 


A 


60.5 


17.9 


60.5 


29.7 




B 


66.6 


22.0 


63.2 


35.7 


147 


C 


67.3 


53.5 


67.6 


18.2 


39 


A 


57.2 


15.5 


57.7 


50.6 




B 


61.6 


9.5 


64.4 


52,5 


59 


A 


58.8 


94.6 


58.7 


157 




B 


65.4 


62.1 


61.9 


182 




C 


68.2 


153 


69.1 


235 


73 


A 


60.1 


58.4 


60.8 


41.2 




B 


65.3 


16.3 


66.6 


47.1 


2 Bx. 


B 


70.4 


57.0 


67.7 


19.6 




C 


69.1 


54.8 


66.1 


28.6 


22 


B 


69.6 


51.8 


67.7 


11.1 




C 


68.1 


22.7 


66.3 


16.1 


165 


B 


69.6 


50.4 


67.6 


66.0 




C 


70.9 


105 


68.6 


180 


33 Ek. 


B 


— 




69.4 


76.2 




C 


— 




70.6 


109 


115 


B 


— 




67.6 


30.4* 




C 


(< 




67.6 


47.2* 


97 


B 






66.7 


52.6 




C 






67.6 


40.7 



*This is absence illness only. 

Whenever temperatures are over 68 degrees, the warmer rooms have the 
greater sickness, regardless of whether Type B or C. When temperatures 
are below 68, the window rooms have less sickness in four instances and 
more sickness in two instances. 

It may be pointed out in this connection that even where the temperatures 
of a fan and Avindow room, as measured at the three-foot level, are identical, 
the window room is actually cooler, for the temperature at the floor level is al- 
ways lower in the window rooms. 

20 



The second means of shedding light on the significance of the grand av- 
erages is by equalizing the influence of each school in each ventilation group. 
In doing this we have combined the two studies, omitting the schools that 
were not represented in both. Where there are 9 rooms at a school, 6 in 
Type A and 3 in Type B, we have reduced the number in the first type to three 
by averaging the two highest readings, the two lowest and the two interme- 
diate. Where there are four readings, we have averaged the two highest and 
used the other two as they stand.* 

We have illustrated in Tables XVIII and XIX the manner of making 
this computation by showing the selected rates used along with the original 
figures. 

In Table XX will be found the averages of the rates both actual and ad- 

Table XVIII 

Actual and Selected Respiratory Illness Rates by Rooms 
Comparison of Types A and B (Both Studies Combined) 







ABSENCE 


RATE 




ILLNESS IN ATTENDANCE 


RATE 




TYPE A 


TYPE B 


TYPE A 


TYPE B 


SCHOOL 


ACTUAL 


SELECTED 


ACTUAL 


SELECTED 


ACTUAL 


SELECTED 


ACTUAL 


SELECTED 


12 


15. 


15. 


4.5 


4.5 


10. 


10. 


15. 


15. 




8.6 


8.6 


11.3 


11.3 


3. 


3. 


14 


14. 




5.0 


5.0 


5.1 


5.1 


16. 


16. 


17. 


17. 




3.9 


■ 3.9 


9.5 


9.5 


47. 


47. 


33. 


33. 




8.1 


8.1 


15.9 


15.9 


14. 


14. 


31. 


31. 




11.1 


11.1 


9.9 


9.9 


14. 


14. 


6. 


6. 


39 


11. 
11. 


11. 


6.9 

21. 


6.9 
21. 


2. 
2. 


2. 


0. 


0. 




14. 


14. 


1.4 


1.4 


2. 


1. 


1. 


1. 




14 








.6 










21 


19. 




















17 



















6.9 


6.8 


10.9 


10.9 


65. 


55. 


34. 


34. 




6.7 




8.6 


8.6 


46 










9.3 


10.5 


2.9 


2.9 


40 


35. 


43. 


43. 




11.7 








30 










13.0 


17.3 






25. 


21. 


58. 


58. 




21.6 








18. 








59 


.6 
.6 


.6 


15.1 
10.9 


15.1 
10.9 


210. 
91 


151. 


61. 


61. 




8.2 


8.4 


1.5 


1.5 


72. 


47. 


91. 


91. 




8.5 








21. 










5.8 


5.8 






74. 


74. 


15. 


15. 




26.8 




3.7 


3.7 


213. 










9.2 


18. 


16.2 


16.2 


165 


189. 


187. 


187. 




8.5 






10. 


124 










8. 


8.3 






91 


108 


158. 


158. 




4.3 








144 










3.0 


3.8 






150. 


147. 




173. 




4. 








147. 








73 


25.8 


18.8 


3.2 


3.2 


57. 


57. 


1. 


1. 




11.5 




10.2 


10.2 


34. 


34. 


1. 


1. 




6.4 


6.4 


10.4 


10.4 


32. 


32. 


24. 


24. 




10.8 


10.8 
















11.6 


8.9 


9.7 


9.7 


42. 


42. 


23. 


23. 




6.2 




2.7 


2.7 


35. 


35. 


41. 


41. 




6.1 


6.1 


16. 


16. 


18. 


18. 


51. 


51. 




5.1 


5.1 















*This might he done by averaging the two lowest or the two intermediate rates, letting the 
highest value stand. The difference, however, is too slight to alter the final result. 

21 



SCHOOL 



Table XIX 

Actual and Selected Respikatouy Illness Rates by Rooms 
Comparison of Types B and C (Both Studies Combined) 



absence R.VTES 
TYPE B TYPE C 

ACTUAL SELECTED ACTUAL SELECTED 



ILLNESS IN ATTENDANCE RATES 
TYPE B TYPE C 

ACTUAL .SELECTED ACTUAL SELECTED 



2 Bx. 


3.1 


3.1 


13. 


13. 


36. 


36. 


64. 


64. 




31. 


31. 


.8 


.8 


38. 


38. 


33. 


33. 




16.4 


16.4 


13.3 


13.3 


47. 


47. 


47. 


47. 




10.7 


10.7 


22.4 


22.4 


10. 


10. 


26 


26. 




7.7 


7.7 


13.2 


13.2 


6. 


6. 


17. 


17. 




11.6 


11.6 


1.3 


1.3 


12. 


12. 


4. 


4. 


22 


5.7 


5.7 


7.0 


7.0 


7. 


7. 


4. 


4. 




8.5 


8.5 


10.5 


10.5 


7. 


7. 


12 


12. 




8.0 


8.0 


8.9 


8.9 








25. 


25. 










4.8 


4.8 








6. 


6. 




5.5 


5.5 


3.5 


3.5 


3. 


o 


1. 


1. 




.9 


.9 


14.4 


14.4 


25. 


25. 


18. 


18, 


59 


15.1 


15.1 


17.9 


17.4 


61. 


61. 


188. 


176 




10.9 


10.9 


16.9 




91. 


91. 


163. 






1.5 


1.5 


16.8 

12.6 

10.4 

8.0 


14.7 
9.2 


15. 


15. 


149. 
140. 

97. 

97. 


145. 

97. 




3.7 


3.7 


16.8 


15.4 


187. 


187. 


316 


296. 




16.2 


16.2 


13.9 




158. 


158. 


275. 








10. 


12.4 
9.9 
9.1 
8.3 


11.2 

8.7 




173. 


256. 
197. 
182 
112. 


227. 
147. 


12 & 


4.5 


4.5 


8.4 


8.4 


15. 


15. 


46. 


46. 


147 


11.3 


11.3 


1.5 


1.5 


14. 


14. 


73. 


73. 




5.1 


5.1 


9.6 


9.6 


17. 


17. 


22. 


22. 




9.5 


9.5 


16.6 


16.6 


33. 


33. 


12. 


12. 




15.9 


15.9 


3.6 


3.6 


31. 


31. 


7. 


7. 




9.9 


9.9 


4.2 


4.2 


6. 


6. 


12. 


12. 


165 


10.4 


10.4 


37.0 


36.1 


21. 


21. 


156. 


119. 




5.7 


5.7 


35.0 




38. 


38. 


82. 






26.4 


26.4 


34 
12. 


34. 
12. 


48. 


48. 


34. 
34. 


34. 
34. 




1.3 


1.3 


11.9 


11. 


99. 


99. 


196. 


189. 




10.4 


10.4 


10. 




56. 


56. 


181. 






8.1 


8.1 


5.3 
1.8 


5.3 
1.8 


33. 


33. 


154. 
151. 


154. 
151. 



justed. Where the school influence is thus equalized in each ventilation type 
the average illness rates are appreciably different from the uncorrected av- 
erages. In the comparison of Types A and B only those schools have been 
used which possessed both A and B rooms. A B room in a school not having 

Table XX 
Comparative Rates of Respiratory Illness with Uncorrected and Balanced Averages 

(Both Studies Combined) 



ventilation 




ABSENCE 


PATE 




illness 


IN ATTENDANCE BATE 


TYPE 


uncorrected 




BALANCED 


UNCORRECTED 


BALANCED 


A 


10.0 






9.6 


• 57 




48 


B 


9.0 






9.1 


39 




45 


B 


9.4 






9.4 


38 




43 


C 


12.0 






11.1 


94 




73 



22 



an A room is omitted. Similarly, in the comparisons of B and C rooms, B 
rooms are omitted where there is lacking a C room in the same school. 

Before correcting for number of rooms the absence rates for A and B were 
10.0 and 9.0. After eliminating the abnormal influence of the schools Avith 
the most rooms, the rates are 9.6 and 9.1. In the first instance Type A was 
greater than B, largely because of the greater number of rooms at Schools 
39 and 59, where the rates are higher. 

The effect of eliminating the school influence is even more noticeable with 
the rates for illness in attendance. Without correction the rate for A was 
57 and for B, 39, an appreciable difference. When the influence of each 
school has been equalized, the rates are 48 for A and 45 for B. In the former 
instance A exceeds B only because it possessed more rooms at P. S. 59, where 
the rates are high, and not because of any ventilation influence. 

The corrected absence rates for Types B and C are 9.4 and 11.1, a differ- 
ence of 1.7. Before the correction had been applied the rates were 9.4 and 12.0, 
a difference of 2.6. It was the greater number of rooms at P. S. 59, where 
the rates are high, that raised the average for Type C. When this influence 
is modified the difference between the two types is less. 

A marked alteration is also produced in the rates for illness-in-attendance. 
Without the correction for number of rooms, the figure for B is 3'8 and for C, 
94, a difference of 56. Eliminating the school influence the rates are 43 
and 73, a difference of only 30. School 59 is largely to blame for the apparent 
wide difference in the types. With an equal number of rooms at each school 
we obtain a truer conception of the difference in ventilation types. 

Having arrived at comparative figures which are believed to give a fairly 
accurate measure of the ventilation influence, we are confronted with the 
interpretation of these results. Is the difference of 0.5 between the absence 
rate in A and B signiflcant, or is it a chance result which, if the experiment 
were repeated, would reverse itself? We can answer this question by deter- 
mining the probable error of the averages. If the differences are statisti- 
cally significant, they will represent at least three times the value of the prob- 
able error. If the differences are no greater than the probable error, then 
we cannot say that ventilation exercises an unmistakable effect on the health 
of these school children. 

The formula for the probable error is 



P. E. — 0.6745 



V^ 



The computation of the probable error is made by averaging the absence 
rates in each type: finding the deviation of each rate from the average; squar- 
ing each deviation; averaging these squares; determining the square root from 
this average; dividing this figure by the square root of the number of cases, 
which gives the standard deviation and finally multiplying this figure by the 
constant, 0.6745, which gives the probable error, or P. E. 

■The difference in the absence rates between Types A and B, 0.5, is less 
than the probable error, or approximately 0.7, and in consequence, is without 
significance. This means that the evidence is insufficient to prove that either 

2^ 



■5 8- 
Ji 3.0. 

a o l"- 

3 O L 

Vi ua 

to 

C 

o (0 






0) m 2 

r o 

;:; H o 

2 ^ c 

a <» 

« > 



^ 

U O +- 
C L p 






I Is 



Ll 



I I. 

H 

1 




i 



JJ 



CO 



CQ 



O 






43 

E 

D 
S C C 






2 c 



t 2 f 



i t: 8 

5 w u 
o — 



O w 

r 

-I 







z 

UJ 



i ^S 



o J. 

1- Q. 

ID 3 



:C^ 



8 = 



^ t> V 



3 r K 

a s V 
« E 
^8 






i £ 

o 

c >- 



^ « 



\j — ^ w € . 

•t- 01 3 ,2 

o o * 
' I I 

< m o 

>* X >^ 



24 



type of ventilation is superior to the other in so far as respiratory illness is 
concerned. 

Eespiratory illness of a less severe nature and sufficient to keep children 
out of school is likewise, judging by the fact that the probable error exceeds 
the difference in rates, no different in a cold, window ventilated room with a 
temperature around 59 degrees than in a cool, window ventilated room whose 
temperature is in the neighborhood of 64 degrees. This finding is in agree- 
ment with the original computations for the entire group of rooms. 

The differences between Types B and C are more marked. The higher 
probable error for absence rates, that is for Type C, is 1.0. The difference 

Table XXI 

Probable Error op Eespiratory Sickness Eates 
(Both Studies Combined) 





difference between 


PROBABLE 


DIFFERENCE BETWEEN 


PROBABLE 




VENTILATION 


types 


ERROR 


VENTILATION 


TYPES 


ERROR 




A 


AND 


B 




B 


AND 


C 




Absence 
Eate 




0.5 




A± .69 

B.± .71 




1.7 




A± .88 
B ± 1.00 


Sickness in 
Attendance 
Eate 




3.0 




A ±6.9 
B ± 7.3 




30 




A ±6.1 
B±9.0 



(Note: Only schools used in both studies are included in the above.) 

between the sickness rates is 1.7. While this difference is not greater than 
three times the probable error, the mere fact that it is greater suggests at 
least a tendency for Type C rooms to be more conducive to respiratory illness 
than those of Type B, 

Minor respiratory illness insufficient to cause absence amounts to a rate 
of 43 in Type B rooms and to 73 in Type C. This is a difference of 30. 
The greater probable error is 9.0. The difference is thus more than three 
times the probable error and statistically may be regarded as significant. 
Interpreted in other words the system of fan ventilation representing Type 
C is more conducive to respiratory illness among school children than the 
window ventilation methods of Type B. 

In .Chart III are represented graphically the absence rates as well as 
other facts pertinent to the matter. The difference in average temperature 
between Type A and B rooms was 4.8 degrees. Relative humidity was almost 
identical, being 46 per cent in the A rooms and 45 in B. The A rooms were 
judged exceptionally fresh 63 per cent of the time as against 31 per cent 
for B. The air possessed a noticeable odor 11 per cent of the time in A and 
15 per cent in B. The degree of congestion was the same in both types, 
namely: 11.5 square feet of floor space per pupil. 

In the second comparison, the Type B rooms averaged 67.0 degrees 
temperature as against 68.1 for the C rooms, a difference of but 1.1 degrees. 
Relative humidity was 38 per cent in B and 40 per cent in C. The B rooms 
were judged exceptionally fresh 18 per cent of the time, the C rooms 22 per 
cent. Odor was noticeable 17 per cent of the sessions in B and only 14 in C. 



The B rooms were apprecial)ly more congested, the square feet of floor space 
per pupil being 11.1 as against 14.7 in the C rooms. 

The following conclusions appear justified from the evidence: 

1. Kespiratory sickness is no greater in a window ventilated schoolroom 
kept around 59 degrees than it is in a room where temperature is 64. 

2. Respiratory sickness is greater in fan ventilated rooms, such as are 
represented in this study, than in window ventilated rooms, even though there 
is not more than a degree difference in temperature, and the fan rooms are 
more spacious. 

3. It is low temperature rather than chemical purity of the air which 
conveys the sensation of freshness. 

DISCUSSION OF VENTILATION TYPES REPRESENTED IN THIS STUDY 

The conclusions arrived at in discussing the relation of ventilation to colds 
raise the question as to whether all methods of school building ventilation by 
mechanical means are discredited by this test. This inference is of course 
unwarranted. The results of this study apply only to the types of ventilation 
here represented, a brief description of which will be given. 

The selection of schools was made by the writer after a conference with 
Mr. Frank G. McCann, heating and ventilating engineer of the New York 
City Board of Education. Altogether over fifty schools were considered, and 
more than half of this number were visited in person by the writer. 

There were many factors to weigh in making the selection. It was de- 
sired above all to choose schools possessing all three types of ventilation. As 
previously explained, this was found impossible except for one school. These 
conditions were nearly fulfilled in one other instance where the three types 
were found in two schools within a block or so of each other. For conven- 
ience it was desirable that the schools should be located within Manhattan and 
Bronx Boros. To represent this territory, selections were made in Lower 
Manhattan, Central Manhattan and Upper Manhattan and the Bronx. It 
was further desired that the ventilation methods should have already been in 
use for some time prior to the experiment, so that uniform operating condi- 
tions would be established. It was possible to adhere to this requirement in all 
but one school, 165, in the first study and all but four in the second. In 
these four, 165, 97, 115 and 33 Bx., window ventilation was arranged by block- 
ing off the fan supply inlets to the rooms and by installing deflectors at the 
windows. The effort was made to select schools whose mechanical ventilation 
equipment was in good condition and in capable hands. Lastly it was essen- 
tial that the principal of the school should be in sympathy with the objects 
of the study. 

Schools 12, 147 and 22 were located in lower Manhattan, the first on Mad- 
ison and Jackson Streets; the second on Henry and Gouverneur, and the 
third on Stanton and Sheriff. Schools 59 and 73 were in Central Manhattan, 
the former on 57th Street near Third Avenue, the latter on 46th Street near 

26 



Third Avenue. School 165 was on 109th Street near Broadway; 39 on 126th 
street near Second Avenue; 2 Bx. on 169th Street near Third Avenue. The 
schools added in the second study were 97 on Mangin Street between Stanton 
and Houston, in the lower East Side ; 115 on 176th Street near Audobon Avenue ; 
33 Bx. qn 184th Street and Jerome Avenue, Bronx; 51 Bx. on Trinity and 
Jackson Avenues, Bronx. 

The date of erection of each building, as well as the type of building ven- 
tilation is shown in Table XXII: 

Table XXII 



SCHOOL 


DATE OP ERECTION 
AND ADDITIONS 


AERATION 


HEAT CONTROL 




REMARKS 


12 


1908 


Window and Grav. Exhaust 


Thermostatic 






147 


1898 


Plenum Fan and Grav. Exh. 


" 






22 


1843-1873-1891-1902 


( < 1 1 { t (I { i 


( ( 






73 


1880-1902 


Windows and Grav. Exhaust 


Manual 






. 59 


1871-1904-1908 


Plenum Fan and Grav. Exh. 


Thermostatic 


Also 


air washer 


165 


1898-1905 


( ( 11 < ( 11 (4 


( ( 






39 


1903 


Windows and Grav. Exh. 


( ( 






2 Bx. 


1874-1886-1902 


Plenum Fan and Grav. Exh. 


( ( 






51 Bx. 


1915 


Plenum and Exhaust Fans* 


(( 


Also 


air washer* 


33 Bx. 


1899 


Plenum Fan and Grav. Exh. 


<( 






115 


1914 


Plenum Fan and Grav. Exh. 


t( 


Also 


humidifying fan 


97 


1915 


i I < ( 11 it ( ( 


<< 


Also 


air washer 



*This refers only to the two rooms used in the study. 

The window ventilated rooms had direct radiation beneath the windows. 
In the first study there were no deflectors except at School 73. In the second 
study deflectors were provided in all rooms of Type A and B. All of these 
rooms had gravity exhaust openings to permit air circulation. It is best that 
these openings be in the inside wall opposite the windows. This arrangement 
did not exist in many rooms, the openings being in walls adjacent to the 
windows and frequently so small in size as to be really of little service in keep- 
ing the room well aerated. . Direct radiation was thermostatically controlled 
in all cases save in School 73, where it was manually controlled. 

The mechanical ventilation consisted usually of plenum fans, air being 
driven into the classrooms near the ceiling and leaving through gravity exhaust 
openings near the floor. These rooms were also provided with direct radia- 
tion under thermostatic control. A check on the ventilation was had by means 
of ribbons on the inlet. These were observed by the nurses, who could thus 
tell in a rough way the efficiency of the blowers. 

The system at School 147 gave a weak and irregular air flow to the three 
classrooms during the first study, and windows were frequently opened. This 
condition was greatly improved in the second study. 

School 22 had a plenum fan system in the new wing. The air flow in the 
rooms was continuous and pronounced, and windows were rarely opened. 
Anemometer readings at the register face made on January 8, 1917, showed 
1640 cubic feet per minute in Eoom 402, 1960 in 403 and 1620 in Room 404. 

School 59 had a plenum fan system in the new addition built in 1908. This 
consisted of two blowers and an air washer. This equipment was in most capable 

27 



hands, and the rooms were at all times well flushed with humidified and washed 
air. Windows were always kept closed. On January 15, 1917, anemometer 
measurements showed the following air flow in cubic feet per minute : Room 
203—1400, 205—1300, 206—1740, 501—1150, 503—1380, 505—760. During 
both studies there was continuous and pronounced flow in all rooms. 

School 165 had a plenum fan system with gravity exhaust which proved 
inadequate for the rooms used in the study. At times air flow was ample, 
again deficient. Conditions were better in the second study. 

School 2 Bx. consisted of an old and new section, the latter built in 1902. 
This section contained the plenum fan ventilating equipment with gravity ex- 
haust. Air flow was fairly continuous and pronounced. 

The orientation of the classrooms varied somewhat in the three types, 
the A rooms having a greater amount of southern exposure. 

Table XXIII 
Orientation of Classrooms in First Study 



VENTILATION 
TYPE 



N., N. E., 
N. W. 



W. 



S., S. E., 
S. W. 



12 
4 
3 



RESULTS IN NEWER SCHOOLS ADDED IN SECOND STUDY 

When this study was begun, there were no schools erected within two or 
three years which could be used. In the second study we were enabled to 
add four schools, three of which had just been opened to pupils within the 
year. School 51 Bx. contained two rooms in which the Ventilation Commis- 
sion was making studies on the effect of humidification, both being ventilated 
by plenum and exhaust fans. These results were included in the grand 
totals, but of course they do not furnish us with a comparison of the types 
forming the basis of this study. The respiratory sickness rates were higher 
in the humidified room. Temperature was about the same in both. Odor 
was frequently noticeable in the humidified room. 

Table XXIV 
Respiratory Illness in School 51 





ABSENCE 
RATE 


SICKNESS 
IN AT- 
TENDANCE 
RATE 


TOTAL 

RES P. 

SICKNESS 

RATE 


TEMPERA- 
TURE 


RELATIVE 
HUMIDITY 


PER CENT 


SESSIONS 


VENTILATION 
TYPE 


ESP. 
FRESH 


ODOROUS 


Humidified 
Not Humidified 


4.0 
14.7 


148. 
50. 


152. 
64.7 


67.6 
67.4 


44 

29 






39 

2 



School 33 was an older building, but because of w^ork already in prog- 
ress there by the Ventilation Commission, the sickness records were also col- 
lected and added to the grand totals of this study. Ventilation was by 



means of plenum fans and gravity exhaust. The fan inlets were blocked off 
in the Type B rooms and deflectors placed at the windows. The respiratory 
sickness rates were less in the two window ventilated rooms than in the 
two of Type C. The fan rooms- were slightly warmer but less odorous. 



Table XXV 
Respiratory Illness in School 33 





ABSENCE 


SICKNESS 


TOTAL 


TEMPERA- 


RELATIVE 


PER CENT 


SESSIONS 


VENTILATION 


ESP. 


ODOROUS 


TYPE 


RATE 


IN AT- 
TENDANCE 
RATE 


RESP. 

SICKNESS 

RATE 


TURE 


HUMIDITY 


FRESH 




B 


24.2 


52 


76.2 


69.4 


34 


1 


15 


C 


37.0 


72 


109.0 


70.6 


30 


2 


3 



School 97 was just completed in 1915 and was equipped with plenum 
fans and gravity exhaust, the air being washed and humidified before entering 
the rooms. Three rooms were chosen to represent each of Type B and C. 
The respiratory sickness rates were the lowest here of all the schools. Sickness 
was less in the fan ventilated rooms than in the window rooms. The fan 
rooms were a degree warmer and were much better aerated. 

Table XXVI 
Respiratory Illness in School 97 





ABSENCE 
RATE 


SICKNESS 
IN AT- 
TENDANCE 
RATE 


TOTAL 

RESP. 

SICKNESS 

RATE 


TEMPERA- 
TURE 


RELATIVE 
HUMIDITY 


PER 


CENT 


SESSIONS 


VENTILATION 
TYPE 


ESP. 
FRESH 


ODOROUS 


B 
C 


5.6 
3.7 


47 
37 


52.6 

40.7 


66.7 
67.6 


42 

43 


49 
85 




32 
3 



The location of this school was along the East River, and across the 
street was a large stable whose odors were frequently wafted over to the 
school at times of east wind. This interfered with the free use of the windows. 
The fan ventilated rooms were not troubled by these odors. One of the three 
window rooms was on an enclosed court which also cut down free air circu- 
lation. The experience at this school was very suggestive. Here was an il- 
lustration where fan ventilation provided a more satisfactory result than 
window ventilation. Schools with similar locations in the neighborhood of 
noxious odors are evidently better served by indirect washed air than by tak- 
ing air direct from the windows. The teacher of one window room was 
well satisfied and much preferred it to the fan ventilation of the building. 
The majority opinion, however, favored the fan rooms. 

School 115, erected in 1914, was equipped with plenum fans, a humidifying 
pan and gravity exhaust ducts. Air flow was at all times ample. Little or 
no use was made of the humidifying pan, Respiratory sickness was greater 
in the fan ventilated rooms. 



29 



Table XXVII 
Eespikatory Illness at School 115 





absence 

KATE 


TEMPERATURE 


RELATIVE 
HUMIDITY 


PER CENT 


SESSIONS 


VENTILATION 
TYPE 


ESP. 
FRESH 


ODOROUS 


B 

C 


30.4 

47.2 


67.6 
67.6 


28. 
26. 


2 
1 


3 
6 



(Note: The comparative data on sickness among pupils in School are not available for 
this school.) 

A great deal of dissatisfaction with the fan ventilation existed among 
the teachers in this school. Complaints of dryness and drafts were common. 
The window rooms were by far the more comfortable. 

In the three schools added in the second study, where Types B and C were 
studied, the window rooms showed less respiratory illness in two, and more 
in one. This supports the findings in the other schools. 

In view of the favorable showing for fan ventilation in a very modern 
school Avith humidification such as 97, it may appear that the results of this 
study do not apply to installations of the latest design. It is true that we 
cannot generalize too widely in the matter, but on the other hand, School 59 
possessed very modern equipment and was operated in every way as per- 
fectly as 97, and yet the sickness rates here were higher than in the other rooms 
crudely equipped for window ventilation. 

The buildings used were representative of what existed in New York City 
at the time. All were not of the very latest construction; nor were all of 
ancient pattern and design. All types were represented. The buildings 
were equipped and built with plenum fan ventilating systems. These systems 
were not ideal. They possessed faults as judged from the ventilating engi- 
neer's viewpoint of the year 1915. 

The rooms fitted up for windoAV ventilation Avere not built for this pur- 
pose. They were altered for the plan in mind. In no instance were the fa- 
cilities complete. 

As a comparison of average fan ventilation in New York City school build- 
ings and ventilation of the same buildings without fans, the present study 
is entirely fair. If either type of room is lacking in its equipment, it is the 
window ventilated rooms which labored under the greater handicap. 

METHODS OF RECORD TAKING 

A word may be devoted here to the method of collecting records. 

Each classroom was visited morning and afternoon. In the morning a 
record was made of the pupils absent and of the pupils in attendance who 
exhibited signs' of a cold. The cause of absence was ascertained by a visit to 
•the home. If a physician were in attendance his diagnosis Avas accepted. If 
no physician were in attendance, the nurse diagnosed the case, and when in 
doubt, her opinion was checked by a medical inspector. Many absences were 
not due to illness, as the subsequent records will indicate. 

The diagnosis of minor illness among pupils in school was made by the 

30 



nurse. Many pupils with symptoms of a cold were pointed out to the nurse 
by the teachers. 

At the beginning of the afternoon session the nurse again visited each 
room to ascertain absences, and the causes were determined in the usual man- 
ner. No effort was made at this time to determine illnesses among those pres- 
ent. A child recorded as having coryza in the morning was credited with 
the same affection in the afternoon if he or she were present in school. 

In addition to the routine described above, the nurse entered each class- 
room at about 10:30 a.m. and 2:15 p.m., or just prior to the midsession 
aeration of the room, and recorded her impressions of the air conditions and 
made determinations of temperature and humidity with a sliiig psychrometer. 
The actual procedure was to enter the room, walk down the side aisle to the 
rear and thence up the middle aisle to the center of the room. The impres- 
sion of odor was then recorded in terms of the scale given below. Next 
in order were recorded the sensations of temperature, moisture and air motion 
in terms as shown. The psychrometer was then swung at a level of about 
three to four feet from the floor, the wet bulb having been moistened from a 
small bottle of water carried for the purpose, and both wet and dry bulb 
readings noted. 

Voting Scales of Sense Impressions 



ODOR 




TEMPERATURE 




MOISTURE 




AIR MOTION 




Exceptionally 










fresh 


1 


Too warm 


40 


Moist 


B 


Dead 


R 


Odor absent 


2 


Satisfactory 


30 


Neutral 


C 


. Bet. R & T. 
Breezy or 


S 


Odor 


3 


Cool 


20 


Dry 


D 


drafty 


T 



Before departing, the nurse made notations of the position of windows, 
whether open or closed, position of door and transom and activity of flag at- 
tached to the inlet register in the fan ventilated rooms. 

Prior to the beginning of the study the nurses were carefully rehearsed 
in their duties and were given demonstrations in the use of the sling psy- 
chrometer. 

The diagnosing of respiratory illness was frequently checked up by 
medical school inspectors and the supervising physician of the study, Dr. Leo- 
pold Marcus. 

For several weeks during the second study all diagnoses were made by 
medical inspectors. Their opinions fully confirmed the interpretations made 
by the nurses and verified the casual inspections of physicians made prior to 
this time. 

Kespiratory illness is responsible for 19 per cent of absences from school ; 
illness other than respiratory (including, however, the acute contagious dis- 
eases) 37 per cent; and causes other than illness 44 per cent. 

THE SCHOOL PERSONNEL AND RESPIRATORY ILLNESS 

The personnel of the pupils is a marked factor in determining the respira- 
tory illness rates distinct from environmental influences. This was recognized 
at the outset, and an attempt, but partially successful, was made to equalize 

31 



this influence among the three ventilation types. Some schools were high in 
respiratory illness in both studies, while others were low in both. 

Considering the total respiratory illness rates for both studies, Schools 
12 and 147 had the lowest figures. These schools are on the lower East Side 
in the heart of the Russian-JcAvish districts. The buildings are old. The 
average temperature was around 64 degrees. These two schools may be 
contrasted with Schools 165 and 115, which were located in very good neigh- 
borhoods and were attended by native born children of well-to-do parents. 
Both are of more recent construction than 12 and 147, P. S. 115 having been 
erected in 1914. In spite of environmental and social advantages, the upper 
Manhattan schools had high rates from respiratory illness. 

In general, the schools located in congested districts and attended by 
pupils of inferior economic and sanitary status had less illness than those 
located in the better class neighborhoods. 

Averaging the rates by social and economic status, the above facts stand 
out clearly. 







EESPIKATOET 


ILLNESS KATES 


SOCIAL AND 


SCHOOLS 


AMONG 


THOSE 


ECONOMIC STATUS 


ABSBTNT 


IN 


ATTENDANCE 


Very good 


165, 11.5, 33 


34.7 




78 


Good 


59, 2 Ex., 51 Ex. 


10.6 




85 


Poor 


12, 147, 22, 97, 73 


7.6 




35.4 


Very Poor 


39 


10.8 




21.6 



An explanation of this unexpected result is not easy to give. It prompts 
the query — Does prosperitj^ undermine health and are our children of supe- 
rior social status coddled to their detriment? 

It is entirely possible that the children in the poorer districts acquire a 
more specific immunity by reason of their congested manner of living. It 
has been shown by Vaughan and the writer that the city boy made a hardier 
soldier in our army camps in 1917 and 1918 and was less subject to disease 
than the country boy.* 

It is also possible that the pupils in the poorer neighborhoods become 
"hardened" by slight exposure to cold, the body becoming less sensitive 
to environmental changes. Overheating and overeating are drawbacks to 
which this class is less familiar than their more fortunate schoolmates. In 
many respects material success converts a man into a less perfect physiologic 
machine. As the battle with the elements becomes less severe, the stimula- 
tion to physiological combativeness wanes. Lack of exercise, complex food 
as distinguished from simple coarse food, and life in uniformly and highly 
heated buildings without question weakens the body physically. In these 
statements may be found the explanation of this peculiar distribution of the 
ordinary forms of respiratory illness. 

In view of the fact that the Type C rooms had more girls than the others, 
the question arises as to whether this would not account for the greater ill- 



*"Comniunicable Disease in the National Guard and National Army of the United States JJuring 
the Six Months from September 29, 1917, to March 29, 1918." By Col. V. C. Vaughan and Capt. T. 
G. T. Palmer, Jour, of Laboratory and Clinical Medicine, Vol. Ill, No. II, August, 1918. Tages 693-698. 



ness.** This presupposes that girls are more susceptible to colds than boys, 
a supposition for which there is no justification so far as we know. There is 
no indication of this in the present study. 

In the first study, P. S. 165, Type C had the highest respiratory absence 
rate, yet only 28% of the pupils were girls. The next highest rate was at P. 
S. 2, Bronx, Type B, where 50% of the pupils were girls. The third highest 
rate was at P. S. 165, Type B, where all the pupils were boys. 

P. S. 2, Bronx, Type C, had high illness rates in the second study and yet 
only one-third of the pupils were girls. 

P. S. 12 and 147 had low rates in both studies and the ratio of girls 
to boys was four to one in the first study and three to one in the second. 

TYPES OF EESPIRATOEY ILLNESS 

Lacking the diagnosis of a medical man as to the specific type of respira- 
tory illness in all instances of this study, we cannot publish these facts with 
any degree of certainty. However, we submit the statements of the nurses, 
which it will be remembered were frequently checked by the medical school 
inspectors. 

The most prevalent form of respiratory illness causing absence was ton- 
sillitis, which amounted to 32 per cent of the total. Slightly less prevalent 
were coryza (25%) and bronchitis (22%). Laryngitis and pharyngitis were 
less frequently mentioned. 

Of the illnesses among those present in school, coryza representing 62% of 
the total, is the most prominent. Bronchitis stands second with 20% and 
laryngitis third with 10%. 

Tonsillitis is especially prevalent in the Type C rooms. Other affections 
are greater in Type C, but no one affection seems to be characteristic of any 
ventilation type. 

Illness other than those listed under the term "respiratory illness" were 
due to a great many causes. Diphtheria, scarlet fever, measles and chicken- 
pox were responsible for a small amount of absence, but absence from these 
causes combined amounts to less than that due to tonsillitis alone. In the 
first study the indefinite term "sickness" was given as responsible for more 
absence than any single cause. More specific terms were used in the second 
study. Headache was a frequent cause of absence, being mentioned most 
frequently in the Type C rooms. Appendicitis was responsible for a number 
of absences. A miscellaneous group of innumerable causes makes up the 
bulk of the absence causes. No particular form of illness seems to charac- 
terize any ventilation type. 

WEATHER AND RESPIRATORY ILLNESS 

Although aside from the ventilation question it is of interest to note the 
fluctuations in respiratory illness from week to week and the corresponding 
changes in weather. From the preceding pages it is evident that the indoor 



**The percentage of girls in Type C was 60 in the first study and 54 per cent in the second. 
The figures for Type B were 37 and 31 and for A, 41 and 49. 

33 



atmosphere has an influence on health. By combining the records of all schools 
it will be possible to follow the seasonal change in respiratory illness. 

In Chart IV we have shown the sickness rate in each type of ventilation 
by .weeks along with the room temperature and relative humidity. The data 
for Schools 97, 115 and 51 Bx. are omitted, as records were available only 





FIRST STUDY 

FEB M - APRIS, I9il, 










SECOND STUDr 
OCT 30- JAN.2fc,l9r7 












1 


1 1 1 


L 


y 


"v 




/ 


•■-• 


V 












1 TOTAL FPtSPIRATORr SlfKNtSsI 






/ 














/ 


•■' 




"^^., 


.• 






'' 






"^' 


■^■v 


./ 






\ 

\ 








;>J 






y 


\ 


N 






^ 


— 


A 








-- 




\^ 






/"" 












— 


.X 


•S. 






"^ 


-~- 




--' 


























. . 















































--:.: 






















c 

B~-' 


-r: 


:~Z'. 


I — 


"* 


'V- 


-^ 


^.r- 


— ■ 


•'--'■ 










.__. 


•— ■ 


— 











/ 






\ 




















3--< 


k 






/ 














\ 




X 









^^ ^__ 












ROOM TEMPtRATURE \ 






















1 i 1 




1 



















































/ 


^ 


:5v 


y 




^ 


'V-. 














tiy- 










/ 


V 






^ 


y/ 


/ 


^^ 




/ 








^ 


\ 




■^ 




^i. 


■^, 




\ 


^- 






\ 


.., 








^ 








-^ 
























*''>5 


\ 




^ RELATIVE HUMIDITY 




<^5 


t 








'^<. 


/ 


IN CLASSROOMS 












^ 


^ 






1 1 1 1 





WEEKLY INCIDENCE OF TOTAL RESPIRATORY 

ILLNESS IN CLASSROOMS VARIOUSLY VENTTILATED 

Data from all BcHools included 

t ,«cepf 97, 115, 31 B« 

A- Cold, wi, Jow vtnt.lQfed rooms (oboirt •,%") 

B- Cool, window ^enMoTcd roomo (about 65') 

C- Fan vent. lalod rooms tobout 69') 



Chart IV. 

during the last seven weeks of the second study. The fan ventilation group 
shows the greatest amount, and the window ventilated, moderate temperature, 
the lowest amount of respiratory illness throughout. 

Respiratory illness declines from February to April although the fan ven- 
tilated rooms show the highest point during the middle of March, Colds 



34 



are at a higher level in October than they are in April. In the Type C and 
B rooms colds increase abruptly during the first 5 Aveeks in the Autumn. 
Type C then holds this level. The B rooms fall off and do not rise again until 
January. Colds in the Type A rooms increase gradually from October till 



RESPIRATORY ILLNESS AMONG- SCHOOL CHILDREN 
AND IT'S ASSOCIATION WITH THL WEATHLR 

By Weeks 



FIRST STUDY 

8week3 Feb.M,-Apr. 6,l9ifc 



SECOND STUDY ' 

ek5 Oct. 30, I9I10- Jan 26, .'917 







- r I 1 1 




I 




-— 
















I Total Resptratory Illness Roles 1 


^ 






















V 






















--— 1 


-^ 






"n 
































1 


V 


^ 

























OUTDOOR WEATHER RECORDS 











TTv — 1 




■-. 





































'"--, 


_,--' 


■•--, 



















^'' 










"^-^ 


■->„ 














tr 


--' 


















1 




1=^ — 


1 — 


t 1 






, 




_^ 














^ '^^^t::! ,'„'=iV^"=' "'"■'• ■— ■-■■■1 1 

L; , — ,ln Shijdc 1 , , ) 













































( 


\ 






/ 


\ 




^ 






"^ 


\ 


/ 














\ 






r 


\ 


/ 










\ 


/ 






\ 


X 


\ 




\ 


\ 




J 












\\ 


/ 






N 


-y 


\ 


I 








Vv&r Csni of FbM.ble 

h \ \ 1 


Son 




/ 










\ 


^ 




\ 









1 1 




1 r- 


















M 


veroge Change inTernprrat 




/ 






" 1 


1 


































/ 


\ 






























/ 


\ 




\ 


/ 




\ 


^ 







_, 






■'v. 


— — 


^ 




^ 






















'' 





























_1 






1 






















r 


Mion RelQt.ve Wurr..A\iy 

10 AM - ZPM 










L 


J 








^ 




■\ 








\ 




















/ 






\ 








\ 


/ 


V 








y^ 






^ 


N 


/ 






\ 




y 




V 


/ 















X 


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\ 


/ 






\ 


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/ 


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^'^ 


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\ 








^ 






j 


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1 


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4- 








-4~ 






1 Mean Hours Rain orSncvfoJI 1— 


t — 




"^ 


^ 


i^ 






-V 


-r 






1 1 1 1 1 




^ 























^ 




















1 






















N 












^ 


. 


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y 




^ 












"V 


r^ 






^ 








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H 




n 
















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M'jfi 


^ 


Ho. 


1 


1 


rJ 

















Chart V. 

the first week in December. From this point they decline only to rise again 
the latter part of January. 

Room temperature in the fan ventilated rooms is the most uniform, keep- 
ing quite constantly between 68 and 69 degrees. In the window rooms Type 
B, temperature has a slightly wider variation, from 65 to 68 degrees, but is 
consistently below Type C. In Type A rooms we note a wide variation, 



35 



from 55 to 66. During February and March these rooms run between 50 
and 60, and this is true also in December and January. In April and Novem- 
ber the temperature is from 60 to 65. 

Kelative humidity is greatest in the A rooms. It is lowest in March and 
January. As will be seen from a later chart, humidity is influenced mostly 
by outdoor temperature and next to that by outdoor moisture. 






3 ffS" 



.'^s 




Total Deheatin^ 



The general points to be noted from this chart are that colds are more common 
in fall than in late winter, that even though the room temperature and humid- 
ity in Types B and C are quite similar, there is an appreciable difference in 
the prevalence of colds, and finally that the course of respiratory illness from 
week to week is guided mainly by influences other than the temperature and 
humidity of the classroom. 



36 



That outdoor weather bears a close relationship to colds is illustrated 
by the various graphs on Chart V. Far overshadowing other weather in- 
fluences is temperature. In the spring, colds decrease as the weather becomes 
warmer. In the fall, oncoming cold weather is coincident with increasing 
respiratory affections. 









— ^ 




^ 


























■- 
























































Mild 


Cole 


S 


e 




£0 



Nnt 


suffidient to cans 












abs</ice 1 


rom 


schoo 


1. 





Week Ending 3 




Week End, no 3 lO I7 24 / 8 |5 22 5 I2 19 2fc 



NOV 



DEC. 



2000- 
ISOO 



^ JAN. 



Dfintha frnm R-ip.umonia 



I 



m 



OCT 



NOV. 



DEC 



J/4N. 



THE sequence: of colds and pneumonia 

NEW YORK CITY I9I6-I9I7 

Colds omong 3000 school children expressed 
as a rate per lOOO pupil session negistration 
units. 

Total deaths from pneumonia (all forms) 
in New York City. 



Chart VII. 



What is understood as changeable weather does not have marked influence 
on colds. The third week in February shows an extreme daily change in 
temperature with no accompanying increase in colds. 

Kelative humidity shows wide variations from week to week without corre- 



37 



spending undulations in the sickness curve. The late winter is more blus- 
tery than the fall, and yet colds are less numerous in the windy season. 

Temperature and colds are most closely related. Is it temperature per 
se or the total chilling effect of all weather .elements combined? The formula 
derived by Dr. Leonard Hill of England from his instrument known as the 
kata-thermometer permits us to sum up in a single expression the combined 
deheating effect of cold, evaporation and wind action.* From the mean 
daily outdoor temperature, vapor pressure and wind velocity we have com- 
puted the mean "total H" or total deheating power of the elements. This 
graph has been placed alongside curves for respiratory illness in the 
second study, and mean temperature and a fourth curve labelled "comfort." 
The comfort vote is a summary of the recorded daily impressions of the tem- 
perature feeling of the weather, as judged by three members of the staff 
of the Ventilation Commission. 

The kata and temperature curves closely parallel each other. In some 
respects the kata curve is more closely associated with the rise and fall of 
illness than the temperature curve. Thus, the kata curve shows increasing 
cold for the first four weeks corresponding to increasing illness. The tem- 
perature curve shows no increase in cold in the fourth week over the third. 

Illness falls off as the temperature stabilizes. In the 7th week tempera- 
ture again descends, and sickness picks up. The 10th week is much colder as 
judged by the kata reading although the temperature is no lower. There is 
however, very low humidity and high wind velocity, which are heat extrac- 
tors. These data suggest that it is the total chilling effect of the atmosphere 
rather than low temperature alone that is conducive to illness. 

The curve of outdoor temperature comfort closely parallels the temperature 
curve, more so than the kata curve. 

The sequence of mild colds in November, followed by heavier colds in 
December and then by pneumonia in midwinter, is strongly suggestive of a 
progressive weakening of vitality. Our mid-winter pneumonia peak is thus 
the result of attrition of vital resistance caused, among other things, by acute 
respiratory affections in the months preceding. 

SUMMARY AND CONCLUSIONS 

From the results of this study there appears to be something inherent in 
the indirect method of ventilating schoolrooms by means of forced draught and 
gravity exhaust, as practiced in this study, that is productive of respiratory 
affections, something which is not present in rooms ventilated with windows 
and gravity exhaust. What these unfavorable elements are is not entirely 
clear. Higher temperature is one. Uniformity of temperature and air flow 
is another. Uniformity is characteristic of the fan ventilated room. In an 
unvarying atmosphere the occupants miss that pleasant stimulating effect. 
Evidently the absence of this quality affects health adversely as well as 
comfort. 



*"The Measurement of the Rate of Heat loss at Body Temperature by Convection, Radiation 
and Evaporation." By Leonard Hill, F. R. S., O. W. Griffith and Martin Flack, Philosophical Trans- 
actions of the Royal Society of London. Series B. Vol. 207, pgs. 183-220. 1916. 



38 



The temperature of window ventilated schoolrooms may be reduced as low 
as 59 degrees without increasing the prevalence of colds. 

It must not be inferred that window ventilation as represented in this 
study was. uniformly satisfactory. It was not. As a rule the rooms exposed 
on the east do not fare as well as others. Ample exhaust openings are 
better than those of small area. There is the matter of location of outlets 
with respect to the windows, location, size and control of direct radiation, 
window deflectors, etc, which affect the success of window ventilation. All 
of these factors must be studied. 

In spite of our inadequate knowledge of window ventilation at its best, 
the fact remains that the window rooms of this study, even though of crude 
arrangement and not built originally for the purpose, competed on favorable 
terms, from a hygienic and aesthetic standpoint, with the most elaborate 
and costly fan and duct equipment. The tendency in the past twenty years 
has been away from natural and toward mechanical ventilation. The time 
and effort of the heating and ventilating engineer has been directed toward 
the perfecting of mechanical means for aerating buildings. What would 
the same amount of effort have yielded if expended on the development of 
natural ventilation? Possibly something of great value and at less expense. 
Because window ventilation is practicable for the ordinary schoolroom, 
it does not follow that the assembly room, the theatre and other places 
seating several hundred people can also be dealt with in this manner. Each 
type of enclosure must be handled as a distinct problem. Natural ventilation 
has its limitations. That the schoolroom is not beyond these limitations is 
the indication of this study. 

The factors which, above all others, promote comfort, health and effi- 
ciency are coolness and fluctuating air motion. If the teacher maintains her 
classroom in a changing condition, without draughts, between 64 and 70 
degrees, with the mean lying nearer the lower figure, it matters little from 
a practical standpoint what the other measurements of ventilation indicate. 
To this standard the room properly equipped with window ventilation and 
gravity exhaust, can readily conform. 

In its quantitative effect on respiratory illness .school ventilation is of 
much less moment than the outdoor weather influence. Respiratory affections 
increase with the onset of cold weather. They diminish with the advent of 
mild weather in the spring. Wind and humidity accentuate the temperature in- 
fluence. Sunlight exerts at least a warming influence sufficient to modify 
the unfavorable effect of cold. Abrupt changes in temperature do not in- 
fluence respiratory illness as much as one might expect from everyday 
experience. 

The sanitarian is interested in the prevention of the tremendous increase 
in the mortality from the pneumonias, which occurs in cold weather. If it 
is possible 'to mitigate the unfavorable weather effect by the proper regulation 
of the indoor atmosphere, it behooves the public health fraternity to bend 
every effort toward this goal. The problem is an alluring one. The results 
of this school study hold forth much promise in this direction. 

39 



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